rating: +36+x

Item #: SCP-4523

Object Class: Euclid

Special Containment Procedures: No interaction with SCP-4523 is authorized under any circumstances. In all circumstances necessitating the deployment of Foundation personnel within physical proximity of SCP-4523, dive teams comprised of no fewer than four (4) operatives are to be exclusively used. Dive team members must maintain continuous radio contact among themselves and use Class-B or higher flares to provide constant visibility. Operatives must use a "square" swimming pattern in which two divers lead the group and two follow from the rear. The use of flashlights or other illumination devices, save flares, is strictly disallowed. Loss of radio contact with any member of the dive team is cause for the mission to be immediately aborted and all remaining operatives to return to surface (RTS). No attempts at recovering lost dive team operatives are permitted.

The location of SCP-4523 is currently withheld from public knowledge through several ongoing efforts. Chiefly, all photographs, videos, or descriptions of SCP-4523, including past expeditions and fatalities, are to be removed and transferred to secure Foundation data storage centers for further analysis.

Description: SCP-4523 designates an underwater cave network in the Pacific Ocean, approximately 59km off the coast of California. Due to the nature of SCP-4523 and the consistent failure of Foundation dive teams to thoroughly explore it, the precise depth and complexity of SCP-4523 is unknown. The entrance and first several meters of SCP-4523 are at least 3m across based on the relative ease of passage for human divers in addition to analysis of file footage. No organisms are believed to inhabit SCP-4523 and surrounding marine life has been recorded evading the entrance, providing it with a significant berth. Natural light illuminates the cave for approximately 10-15m before gradually fading out, resulting in a total loss of visibility.

Roughly 30 minutes after being entered by human divers, the entrance to SCP-4523 will become sealed with no other exit methods being apparent. Externally, the entrance will become imperceptible, typically with no indication that it had ever been present. Attempts to relocate the exit have invariably failed, as have attempts to breach the cave using explosives, tunneling devices, or other tools. Communication devices will remain functional until becoming depleted of power or suffering disabling damage, though various audio abnormalities are often present. Stranded divers report a labyrinthian layout with exceptionally complex tunnels branching from the primary shaft, often causing confusion and disorientation.

Death via drowning typically occurs within 24 hours, as this encompasses the air provided by both primary and secondary air tanks. Audio recordings obtained from Foundation dive teams suggest the presence of an unidentified entity provisionally designated SCP-4523-01, described as superficially resembling a tall, emaciated humanoid. The existence of SCP-4523-01 is contested by elements of project staff who hypothesize it is the cadaver of a previous diver, albeit with false properties assigned to it due to confusion or paranoia.

Addendum I: Log 4523-A

The following transcription was obtained from the final thirteen minutes of communication between Agent Robertson (Dive Team 5) and Foundation Central Command (FCC).

Robertson: Team 5 to command, come in.

FCC: Copy, we're receiving.

Robertson: Oxygen down to 29%. Primary flashlight depleted. Switching to reserve. Any word from the rest of the team?

FCC: Negative, Team 5. We're still, uh…still trying to breach the exterior of the cave. Can you see any light?

Robertson: Negative, but - [unidentified noise] - looks like there's a crevice up ahead. Gonna check it out. Standby.

[Robertson can be heard approaching the crevice. The aforementioned unidentified noise becomes audible again.]

Robertson: Command, come in.

FCC: Copy, go ahead.

Robertson: The crevice looks a little narrow, but uh…I'm gonna go for it. I'll have to temporarily disconnect my secondary air tanks and pull them through.

FCC: Five, we strongly recommend you hold position —

Robertson: I can make it. Attaching the flashlight to my wetsuit —

[Unidentified noise]

Robertson (away from microphone): The fuck?

[Unidentified noise grows louder]

Robertson: Command, is there someone in here with me?

FCC: Negative. We have no intelligence on the presence of any other divers within SCP-4523.

Robertson: Copy. Must be hearing things. Attempting to make it through the crevice now.

[Robertson can be heard struggling to pass through the crevice. A hiss can be heard after his tanks are disconnected.]

Robertson: Fuck!


Robertson: I've lost my light — fuck, I can't — [Unidentified noise] — I think my fucking leg is stuck —

FCC: Can you reach your tanks?

Robertson: Negative!

[Robertson's breathing becomes strained. The unidentified noise is now louder than his voice.]

FCC: Five, do you read?

Robertson: There's something in here with me! Fucking — [screaming]

FCC (away from microphone): Get ready to cut the feed.

Robertson: Help me — fuck, oh my God — [screaming]

[Transmission terminated]

Addendum II: Recovery Log 4523-F

On [DATE REDACTED], SCP-4523 began expelling various items later identified as human remains from its entrance. DNA analysis determined these remains belonged to deceased Foundation divers lost within SCP-4523. A partial log of the remains and their conditions is provided below:

Agent Remains Notes
O'Connor Head, neck, upper torso All limbs severed. Severe lacerations present across epidermis. Lower jaw partially severed at the left mandible. All teeth removed with surgical precision. Hair, teeth, and fingernails later found embedded within lower intestines. Primary air tank surgically grafted to the spine.
Hawkins Full body Diving mask appears fused to the skull. Genitalia severed at the midsection.
Johnson Full body Neck fractured due to trauma consistent with a multiple story fall. Skull punctured in three places with roughly 43% of the brain missing. Lungs found to contain considerable quantities of bile.
Ramirez Partial body Left arm severed and placed in throat, partially extending from mouth. Both eyes missing. Severe, open gash found on the lower back; aquatic parasites found in wound.

Addendum III: Log 4523-B

On [DATE REDACTED], the camera feed from Dive Team 3 was reconnected to Foundation Central Command and recorded roughly six hours of footage, showing various portions of SCP-4523. At one point, the camera approaches an unidentified diver fused to the wall of the cave through unknown means. Diver notices the presence of the entity moving the camera and begins screaming through their rebreather, continuing for 45 minutes before the feed cuts to black. Twelve minutes later, the feed reactivates, showing a chain embedded in the diver's torso pulling away from the camera as the diver continues to scream. The remainder of the footage is distorted to the point of being indiscernible, though screaming and sounds of flesh tearing are audible until the connection fails.

Addendum IV: Signal 4523-I

On [DATE REDACTED], the camera feed from Dive Team 3 once again reactivated, showing a portion of the complex for nearly two hours. Some researchers have claimed that an entity resembling a humanoid can be observed on the left side of the frame. In the final frames of the recording, it is speculated that a "smile" can be seen before the feed cuts to black. Low-pitch tones audible in the background were later interpreted as the following morse code message:


The context of this message remains unknown.

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